02 U7B Plants p092-173 12/14/06 3:44 PM Page 92otte.weebly.com/uploads/1/3/8/2/13820598/02a_u7b_plants_p092-12… · 02_U7B_Plants_p092-173 12/14/06 3:44 PM Page 93. Exploring 94

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U N I T

B

02_U7B_Plants_p092-173 12/14/06 3:44 PM Page 92

In this unit, you will cover the following sections:

Understanding structures and life processes of plants helps us to interpret their needs.

1.1 The Body of Seed Plants

1.2 Plant Processes

1.3 Reproduction of Seed Plants

1.4 Plant Structures Vary to Adapt to Their Environment

1.5 Plant Needs and Growing Conditions

Plants play an essential role in the environment and inmeeting human needs.

2.1 The Role of Plants in the Environment

2.2 We Use Plants in Many Ways

2.3 Natural and Managed Resources

Soil is an important resource that human activity can protect or degrade.

3.1 What Is Soil?

3.2 Our Practices Can Improve or Degrade Soil

The ways that plants are grown and used are related tohuman needs, technology, and the environment.

4.1 Modifying Environments to Increase Yields

4.2 New Plant Varieties Are Developed by Selective Breeding

4.3 Controlling Weeds and Pests

4.4 Consequences of Environmental Management

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1.0

2.0

3.0

4.0


Exploring

94 Unit B: Plants for Food and Fibre

Our planet would be a very different place without plants. In thisunit, you will find out why plants are critical for all life on Earth.You will learn about the many ways we use plants, and thetechnologies we use to produce the plants we need. You willinvestigate how plants have adapted to different environmentalconditions. You will take part in activities that will challenge youto come up with real-life solutions to problems that can be causedby the ways we grow plants. Understanding the consequences ofthe changes we make in growing plants will allow you to predictwhen these changes can harm the environment.


95Exploring

SURVIVING IN THE WILDERNESS

Many great stories have been written about people who have foundthemselves stranded and alone in a wild place. Robinson Crusoe,by Daniel Defoe, is one such story about a man who is shipwreckedon a deserted island and has to survive on what he can make orfind.

Do you think you could survive in a wild place? The teenagersin this newspaper article found out the hard way that they couldsurvive in the wilderness of northern Alberta!

Elk Point, Alberta. – Wildberries and boiled leaves androots kept three teens aliveduring a 24-day ordeal on aremote island on Frog Lake,210 km northeast of Edmonton.The teens became stranded afterthe paddleboat they used to getto the island drifted away fromthe shoreline. The trio wasunable to swim off the island,

since the shoreline was an icy 300 m away.

The quick-thinking teensset to work searching for foodand shelter. They made a lean-toand bedding out of pine boughs.They collected edible berries,roots, and leaves. The teens alsocollected twigs for firewoodand were able to light a fire witha cigarette lighter.

Teens Found Alive in Bush

Rescuers airlift survivors to safety.


These young people were able to survive because they usedplants for food, shelter, and warmth. The photographs above showtwo examples of plants that they used.

Our provincial flower, the wild rose, has many parts you caneat. The hips in particular can be an important survival food, sincethey are available throughout the fall and winter. One rose hip cancontain as much vitamin C as an entire orange, as well as otherimportant nutrients.

Balsam fir has soft needles that can provide wonderful bedding.The resin from this tree can also be used to relieve insect bites,sores, or rashes.

How about you? Would you know how to use plants to help yousurvive? With a partner, see if you can name two plants that youcould use. At least one of them should be a plant you can eat.


S U R V I V O R !You and your friends love to spend the weekend camping in the great outdoors.But while you are hiking in the woods, you take a wrong turn and can’t find yourway back. You’re lost!

You might have to stay in the woods for a few days until someone finds you. Allyou have is the clothes you are wearing, a pocketknife, and anything you canfind in the woods.

In a small group, discuss how you could use plants that grow in the woods inyour area to meet your basic needs of food, warmth, and shelter. How long doyou think you could survive?

Give i t a TRY A C T I V I T Y

The teens ate rose hips andslept on boughs.

Safety Caution!Never eat any plantthat you find in thewild unless you aresure what it is.Many plants canmake you sick.


97

FocusOn

SCIENCE AND TECHNOLOGY

Exploring

As you proceed through this unit, you will be asked to organizeyour thoughts around how technology can help us to grow and useplants in a way that doesn’t harm the environment. Many humanactivities are a balance between these two things. You will be askedto think about these ideas as you perform activities and answerquestions throughout this unit.

1. How is the environment affected by the way we produce andharvest plants?

2. What technologies can help us to produce the plants we needand also minimize the impact we have on the environment?

3. What kind of knowledge must we have about plants and theirenvironment to ensure we continue to produce the plants weneed and keep our planet healthy?

The answers to these and other questions about plants will helpyou understand how using plants for our needs relies onknowledge and the use of appropriate methods. The project at theend of the unit is a chance to apply what you have learned bydesigning and building a growth chamber for vegetable seedlings.


You probably know a lot about plants. You might know that mostplants have leaves, at least one stem, and roots. And lots of plantshave flowers. But of course, not all plants are the same. Thinkhow different a cactus is from a pine tree! Do you believe that theyboth have the same parts? It’s true!

Is there anything that you’ve ever wondered about plants?There are so many questions we could ask. Why do they produceflowers? How does a seed work? Let’s take a closer look at plantsand see if we can find answers to some of these questions.

Understanding structures and lifeprocesses of plants helps us tointerpret their needs.

Key ConceptsIn this section, you will learnabout the following keyconcepts:• life processes and structure

of plants• plant propagation and

reproduction

Learning OutcomesWhen you have completed thissection, you will be able to:• describe the parts of a seed

plant• explain the processes that a

plant uses to stay alive• describe the life cycle of seed

plants

1.0

98 For Web links relating to 1.0, visit www.pearsoned.ca/scienceinaction

Do you know what a plant needs to live?


99Understanding Structures and Life Processes of Plants Helps Us to Interpret Their Needs

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P L A N T P A R T C H A R A D E S

Do you think you could describe the parts of a seed plant without speaking outloud? Try it and see!

Your teacher will hand you a card that will have one of these plant parts writtenon it: stem, leaf, root, or flower. When you get your card, read what’s on it andthink about how you might act out your word.

Pick a partner and take turns acting out your words. After you get the correctword, discuss the function of the plant part with your partner.


Figure 1.1 Seed plants are the largest group of plants in the world.

1.1 The Body of Seed PlantsIn this unit, we are going to look only at those plants that makeseeds, or seed plants. Some examples of seed plants that you mighthave seen are daisies, cottonwood trees, wheat, and orchids. As youcan see, seed plants come in all shapes and sizes.

On a clean page in your notebook, sketch a seed plant. It can beany kind of seed plant you want. Label each part, then write downeverything you know about the part in point form beside each label.As you work through this unit, you can look back to your sketchand your notes and add or change anything you want to as you goalong.

The Same, butDifferent

Although they lookvery different, thestructures that makeup these plants are thesame. What are thesestructures?



ProblemSolving

Act iv i ty

DE S I G N A MO D E L O F A SE E D PL A N T

Recognize a NeedYou own a small company that makes displays for museums and science centres.One of your clients needs a model of the structures found in a seed plant. Themodel has to be simple enough for small children to understand, but it has to beaccurate.

The ProblemMake a three-dimensional model of a seed plant.

Criteria for SuccessFor your model to be considered successful, it must• contain all the parts of a seed plant• have labels on all the parts

Brainstorm Ideas1 With a partner, make a list of all the parts that must be included on your

model.2 Draw a sketch of how your finished model will look.3 Make a list of the materials you might use to create your model.

Build Your Model4 Gather your materials and construct

your model.

Test and Evaluate5 Look over your model and check

how well it fits the criteria forsuccess. Make any changes to yourmodel that you think are needed.

6 Set your plant model up in an areadesignated by your teacher. Lookover other students’ models andcompare them with your design.Assess how well the other modelsfit the criteria. Are all the modelsthe same or different? Suggest areason to explain this.

Communicate7 With your partner, write a description of each of the plant parts that are on

your model. Your description should be in a style that would suit a sciencecentre display.

Materials• a collection of craft

materials that could beused to make a model,such as constructionpaper, cardboard, tissuepaper, pipe cleaners, craftsticks, modelling clay



EACH PLANT STRUCTURE HAS A FUNCTION

Seed plants not only have the same kinds of structures, but thesestructures do the same job in all plants.

CHECK AND REFLECT

1. What are the main parts of a seed plant?

2. Draw a diagram of a root or a leaf. Write two or three sentencesbelow your diagram that describe the function of the structureyou choose.

3. Why do plants produce seeds? Name one plant structure thatcan produce seeds.

4. Give three examples of seed plants that grow in your area. Donot use any of the examples from this book.

Flowers• each flower usually has

both male and femaleparts for reproduction

Cones• there are separate male

and female cones forreproduction

Leaves• produce food for the plant• take in and release oxygen

and carbon dioxide• allow water to exit the plant

Seeds• contain an

embryo that will form a new plant

• contain a foodsupply for theembryo

Stems• provide a pathway

for movement ofwater and food

• support the leaves and reproductivestructures

Roots• absorb water and

dissolved nutrients• anchor the plant in

the soil

Figure 1.2 Structures in seed plants



M O V I N G I N T H E R I G H T D I R E C T I O N

Plants can move water from the soil up to their leaves. Animals move fluidsaround their bodies by the pumping action of their hearts. This experimentcan help you understand how plants move fluids.

Put enough water in each beaker so that they are both about one-third full.Mix several drops of food colouring into the water.

Remove the leaves from one stalk of celery. Prop the celery in the beakerso its base is in the water. Place the other stalk that still has its leaves inthe other beaker.

Place both beakers containing the celery stalks under a bright light or in asunny spot for about three hours.

Remove the stalks from the water and cut cross sections from each stalk atseveral places so you can see how far the food colouring moved up thestalk.

Compare the distance the food colouring moved up in the two stalks. Whydo you think this difference occurred?


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Water Me!

More than 90% of thewater a plant takes inis lost through itsleaves. No wonder theyneed to be wateredregularly!

1.2 Plant Processes This tall tree has to move water up from its roots and food down from its leaves. How do plants transport these substances?

You have probably broken or cut a plant apart, so you will know that plants don’t have a heart or a pump to move water and nutrients around. Discuss with a partner how a plant might move substances from one part to another. Have you seen any other examples of fluids moving without being pumped?

Materials &Equipment• water• food colouring• 2 400-mL beakers• 2 stalks of celery

with leaves• small sharp knife or

razor blade

Figure 1.3 Do plants have a pump?



r eSEARCH

Moving UpPlace a plastic bagover a plant and tie itshut. Leave it in asunny window for aday. Explain whathappens using theword “transpiration.”

waterparticles

A PROCESS FOR MOVING WATER UP FROM THE ROOTS

Water moves up a plant from the roots to the leaves by acombination of processes. These processes include the following:• The main process that draws water up from a plant’s roots is

transpiration. Transpiration is the evaporation of water from thesurface of the plant—mainly from the leaves. Water particlesevaporate from the surface of the leaves, and more water particlesmove up within the plant to take their place. This processcontinues down through the plant with particles continuallymoving up from the roots.

• Another process that helps water move up through a plant iscalled capillary action. Water travels from the roots to the leavesthrough tiny tubes in the roots and stems. You may have learnedin other lessons that water particles are attracted to one another.This attraction causes water particles to “stick” to one another.The water particles are also attracted to the sides of the tiny tubes.This attraction, along with the attraction between the waterparticles themselves, helps to move the water up inside the plant.

• Water from the soil enters root cells by a process called osmosis.When the concentration of water in the soil is greater than theconcentration of water in the roots of the plant, water moves intothe root cells. You will learn more about osmosis in thissubsection.

Figure 1.4 When tubes are very narrow, like this glass tube, the force of the attractionof the water particles to the sides of the tube is greater than the force of gravity, so thewater moves up.

Figure 1.5 Water moves into root cells and then travels up tiny tubes to the leaves.Water particles exit through small holes in the leaves. If there is too little water inthe soil, and the plant continues to lose water from its leaves, the plant wilts.


A PROCESS TO MAKE FOOD

Plants make their own food by the process of photosynthesis.Photosynthesis produces a type of sugar.

The leaves of seed plants usually do most of the photosynthesis.Photosynthesis takes place in structures inside the leaves calledchloroplasts. The chloroplasts capture the sun’s energy and use itto join carbon dioxide and water together to make sugar. Thisprocess also produces oxygen.

A PROCESS TO USE FOOD

When plants photosynthesize, they use energy to turn carbondioxide and water into sugar. When plants use this sugar for food,they get energy and produce carbon dioxide and water as waste.This process is called cellular respiration.


Figure 1.6 Plants use the energy from the sun to make their own food.

carbon dioxide

oxygen

energy fromthe sun

water

energy + carbon dioxide + water ➝ sugar + oxygen

Figure 1.7 The wordequation for cellularrespiration.

sugar + oxygen ➝ carbon + water + energydioxide


105

InquiryAct iv i ty

Materials & Equipment• 2 plant cuttings wrapped in

moist towelling• graph paper• 2 small beakers or clear

vials• 10-mL or 25-mL graduated

cylinder• water• plastic wrap• scissors• a sunny window

Understanding Structures and Life Processes of Plants Helps Us to Interpret Their Needs

PL A N T S AT WO R K

The QuestionHow does transpiration move fluids from the roots?

The HypothesisIf evaporation occurs from the surface of the plant, then fluids move up from theroots into the stems and leaves.

Procedure1 Collect two plant cuttings that are about the same size. Carefully remove all

the leaves but one from one cutting. Keep all the leaves on the other.2 Determine the volume of water that will fill the beaker to about 1 cm from the

top. Measure the same volume of water and fill each of two beakers.3 Stretch a sheet of plastic wrap tightly over the top of each beaker. Using a

pencil, punch a hole in the plastic. 4 Cut about 0.5 cm off the bottom of each plant cutting. Place the stem of the

cutting in each beaker of water through the hole in the plastic.5 Put your cuttings in a sunny window and leave them overnight.6 The next day, remove each cutting from its container. Be careful not to lose

any of the water. Using the graduated cylinder, measure the amount of waterthat is left in each of the beakers. Record your findings.

Collecting Data7 Remove the leaves from one cutting. Carefully trace the outline of each leaf

on a piece of graph paper.8 Estimate the area of each leaf by counting the number of squares it fills.

Count any square that is at least half inside the outline.9 Estimate the area of all the leaves and record your findings. You may want to

make a table or use a spreadsheet program.

Analyzing and Interpreting10 Make a bar graph showing the amount of water that was in the two beakers

on the second day. Make a second bar graph that shows the total leaf area ofthe two cuttings.

Forming Conclusions11 Which of the cuttings lost more water? Compare the leaf area of this cutting

with the other.12 Water evaporates from pores on leaves. What do you think happens to the

rate of evaporation if there are fewer leaves on a plant?

Applying and ConnectingHave you ever forgotten to water your house plants, and found that they wilted?Suggest a reason why this happens.

Figure 1.8 Step 7



PROCESSES TO MOVE SUBSTANCES IN AND OUT OF PLANT CELLS

After a plant has made sugar in its leaves by photosynthesis, it musttransport this food throughout its body. It also has to move thewater out of the stem into the rest of its cells.

Figure 1.9 Under the cell wall in the plant cell is a cell membrane that has tiny openings. Thesize of these openings controls what particles can pass through. Particles of water and certainother substances can get in and out of the cell.

As shown in Figure 1.9, the plant cell is surrounded by a membranethat has pores, or tiny openings. Particles of some substances areable to move in and out of a cell through these pores. The cellmembrane acts as a filter, keeping some substances inside the celland allowing some substances to move in and out of the cell. Manyprocesses take place to move substances in and out of plant cells.One of these processes is diffusion. Diffusion takes place whenthere is a difference between the concentration of a substanceinside and outside a cell. Another process that does not require adifference in substance concentration is called active transport.Active transport uses energy to move substances in and out of plantcells.

DiffusionWhen you put a drop of food dye in a glass of water, you get onesmall area with a lot of dye particles and a large area with none. Inother words, there is a higher concentration of dye particles in thedrop of food dye. Concentration is the number of particles of onesubstance in a certain volume of another substance. Diffusion is themovement of particles from an area of high concentration to an areaof low concentration, until there is an equal number of particleseverywhere. Particles that are small enough to fit through themembrane pores in a plant cell move in and out of the cell bydiffusion.

Figure 1.10 The food dyeslowly mixes with the waterdue to diffusion.

chloroplast nucleus

cell wallmembrane

m a t hLinkIf you stirred 3 g ofsugar into 9.3 mL ofwater, how manygrams of sugar wouldbe in each millilitre ofwater?



OsmosisWater is one of the substances that is vital to the survival andhealth of cells. The cell membrane in plant cells allows waterparticles to pass through. If the water concentration inside a cell islower than the water concentration outside, water particles fromoutside move in through the cell membrane. If the waterconcentration inside the cell is higher than outside, the cell loseswater to the outside. Osmosis is a special name given to themovement of water particles through a membrane. Osmosis moveswater particles from a cell with a high water concentration to a cellwith a low water concentration. Water usually moves out of thecells in the stem to the rest of the plant cells.

A PROCESS TO EXCHANGE GASES

In the process of photosynthesis, plants use carbon dioxide gas andproduce oxygen gas. In the process of cellular respiration, plantsuse oxygen and produce carbon dioxide. Gas exchange is theprocess of these gases entering and leaving the plant.

CHECK AND REFLECT

1. What raw materials does a plant require for photosynthesis?What are the products?

2. How are osmosis and diffusion related?

3. Describe three processes that allow water to move from roots toleaves.

4. What do you think would happen to transpiration if a plantwere blowing in a hot, dry wind?

carbondioxide

oxygen

Awater

particles

Bwater

particlesand sugarparticles

Figure 1.11 Thismembrane has pores thatallow the water particles topass through but not thesugar particles. Theconcentration of waterparticles is higher in side Athan in side B, and waterparticles move from A to Bthrough the membrane.This movement of water iscalled osmosis.

Figure 1.12 Oxygen andcarbon dioxide diffusethrough tiny openings inthe leaf.


ExperimentON YOUR OWN


L I G H T A N D P L A N T G R O W T H

Before You Start ...Plants use light to photosynthesize and produce thefood they need to grow. Farmers will sometimes cleartheir fields just to make sure that their crops get asmuch light as possible.

In this activity, you will design an experiment totest whether plants grow faster when they get morelight.

The QuestionDo plants grow faster when they get more light?

Design and Conduct Your Experiment You may wish to use Toolbox 2: The Inquiry Process ofScience to help you plan your experiment.1 Make a hypothesis that will allow you to test the

effect of different amounts of light on the growthrate of plants. (A hypothesis is a possible answerto a question or a possible explanation of asituation.)

2 Decide what materials you’ll need to test yourhypothesis. For example:a) What kind of plants will you use?b) How many plants will you need?c) Will you grow the plants from seed or buy

plants?d) What will you use to supply the light?

3 Plan your procedure. Ask yourself questions suchas:a) What evidence am I looking for to support my

hypothesis?b) What steps will I follow to collect the data I

need?

c) Is the test I’ve designed fair? How do I know?d) How will I record my results? For example, do I

need a data chart? a graph? both? neither?e) How long do I have to complete my

experiment?4 Write up your procedure. Be sure to show it to

your teacher before going further.5 Carry out your experiment.6 Compare your results with your hypothesis. Did

your results support it? If not, what possiblereasons might there be?

7 Share and compare your experimental plan andfindings with your classmates. Did anyone plan anexperiment exactly like yours? similar to yours?How do your results compare with theirs?

Figure 1.13 How will you change the amount of light?



1.3 Reproduction of Seed Plants

A farmer plants wheat seed in the spring and waits for the firstshoots of the crop to appear. In a few weeks, the shoots begin togrow tall and green, and leaves may begin to sprout. By the end ofthe season, the field is covered with healthy plants that have rowsof seeds on their stems.

When the wheat is ready to harvest, the wheat plants have gonethrough an entire life cycle. A life cycle is the stages that a livingthing passes through to go from one generation to the next. For seedplants, the life cycle starts when a seed begins to grow into a plantand ends when that plant produces seeds of its own.

Think about crops grown in your area. Have they gone throughall the stages in their life cycle when they are ready to harvest?

Packaging Palms

This coconut willeventually grow into a tall palm tree.

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T H E S E C R E T O F S E E D S

You are going to look inside some different types of seeds. To make them easierto open, they have been soaked in water beforehand.• Pick up one of each type of seed.• Open each seed by splitting it carefully in half. Examine the inside.• Make a diagram of the structures you see inside each seed. Label any parts

you recognize.

Were all the seeds the same inside? From what you saw, can you explain whathappens when a seed starts to sprout?


Figure 1.14 These wheat seeds are about to begin their life cycle.



Figure 1.16 Seeds containenough food to start thenew plant growing.

Figure 1.18 This plant is anadult because it has flowers.

Figure 1.17 The seedlingneeds plenty of sunlight,nutrients, and water togrow.

THE LIFE CYCLE OF SEED PLANTS

The stages in a life cycle are often drawn as connecting points on acircle. Look at Figure 1.15. What are the stages in the life cycle of aseed plant?

The Seed StageA seed has three main parts: the embryo, stored food, and a seedcoat. The stored food surrounds the embryo in some plant species.In other species, food is stored in part of the embryo itself. Theembryo uses this stored food to survive until it begins tophotosynthesize and produce its own food.

The Seedling StagePlants in the seedling stage grow very fast and produce new leaves,roots, and stems. Seedling plants produce their own food byphotosynthesis, but they also need nutrients from the soil to buildtheir new parts.

The Adult StageA plant is an adult when it produces reproductive structures. Forseed plants, these structures are either a flower or a cone.

Figure 1.15 Seed plants have three stages in their life cycle.

pollinated

adult

seedling

grows anddevelopsreproductivestructures

starts to grow

seed



REPRODUCTION OF SEED PLANTS

PollinationPlants produce flowers and cones only sothey can make seeds. To do this, the adultseed plant needs to undergo the process ofpollination.

The diagram in Figure 1.19 shows theparts of a flower. The male part of the flowerthat is involved in pollination is calledpollen. Pollen grains are small, sticky cells.One plant produces millions of pollen grains.

The female part of the flower is called theovary and is usually in the centre of theblossom. The ovary contains the ovule.Pollination occurs after a pollen grain landson the stigma of the flower, above the ovary(see Figure 1.19). The pollen grain produces apollen tube that grows down from the stigmato the ovule. Through this tube, cells transferfrom the pollen grain to the ovule. The ovulethen grows into a seed.

Plants that produce cones (called conifers) usually have separatemale and female cones. The male cones produce pollen, and thefemale cones contain the ovules. When the ovules are pollinated,seeds develop on the female cones.

PollinatorsPlants need a way to get the pollen to the ovules. Some plantsrelease pollen in the air, where it is carried by the wind. Conifertrees and grain crops are pollinated by wind.

Many flowering plants rely on pollinators, which are organismsthat carry pollen from one flower to another. Birds, insects, andeven bats can be pollinators. Pollinators come to a flower in searchof nectar, a sugary liquid that they eat. As the animal enters theflower, it becomes coated in pollen. When it leaves, it takes thispollen with it and transports it to the next flower.

Many of our crops such as grains and fruits must be pollinated.Growers have found ways to ensure that pollination takes place.Many plants, such as corn, are grown in rows a particular distanceapart to help them be pollinated by the wind. Fruit growers willoften keep beehives near their plants.

Figure 1.20 Many plantsare pollinated by insects.

anther—containspollen grains(male)

ovary—containsovule (female)

stigma

Figure 1.19 Flowers usually have both maleand female parts.



ProblemSolving

Act iv i ty

Materials & Equipment• bean and corn seeds • small plastic bags• absorbent material such as

paper towel, cotton batting,coffee filters, vermiculite

GE R M I N AT I O N A N D GR O W T H

Recognize a NeedSpace is scarce in the greenhouse where you and your colleagues work asresearch technicians. Improvements in the method for growing plants arerequired. There are three possible ideas under consideration. Your group will haveone or more people investigate each idea. Once you are done, you can compareyour results and determine the best method for growing seedlings in thegreenhouse.

The ProblemOne idea is to use plastic bags with moist inserts as a method for starting andstudying seed growth. These bags can be attached to the wall and therefore willnot require table or floor space.The second idea is to use different packing densities for seedling growth. If youcan pack more seedlings into a smaller space, there will be more available tableand floor space.The third idea involves determining the best treatment of seeds to preventmoulding. Because of the space problem, the treated seeds will be germinated insmall plastic bags and tacked to the wall.

Criteria for SuccessFor this activity to be considered successful, you must• decide as a group who will investigate each idea• complete your investigation and collect appropriate data• compare results and determine the best method for growing seedlings in the

greenhouse

Brainstorm Ideas1 Below are the task requirements and materials needed to investigate each

idea. Read all of these so you are aware of what your partners are doing.2 As a group discuss a plan for each idea using the materials available. 3 As a group decide how you will use the same process to measure and record

plant growth.4 Prepare a plan for the idea you are investigating. Have your teacher approve

your plan before carrying it out.

Idea 1 – Using Plastic BagsTask 1To germinate (grow) seeds in a way that allows seedlings to be easily observedand transplanted to soil.



Idea 2 – Using Different Packing DensitiesTask 2To determine how many seeds can be planted in a confined space withoutadversely affecting their growth. Your plan should include growing differentnumbers of seeds (from 2 to 20) in the confined space of a small plastic bag or a7-cm pot.

Idea 3 – Preventing the Formation of MouldTask 3To develop a process that prevents or reduces mould growing on seeds. Preparea plan that will enable you to determine if briefly soaking seeds in vinegar or abaking soda solution is able to prevent mould from growing on the seeds duringgermination. Plastic bags with moistened inserts will be used to germinate theseeds.

Test and Evaluate5 With permission from your teacher, carry out your plan in a safe manner.6 Record your observations and data.7 If possible, prepare a graph from your data.

Communicate8 Work as a group to produce a report. The first section should be your

recommended solution. Use data collected in your investigation to supportyour recommendation. The second section should be three individualsummaries describing the work done by each group. For your summary,include observations and a graph if you were able to make one. How doesyour investigation solve the problem? Discuss any changes you would maketo your investigation if you were to repeat it.

Materials & EquipmentIdea 2• seeds such as corn, beans,

radish, or lettuce• plastic bags or 7-cm pots• absorbent materials such as

paper towel, cotton batting,coffee filters, vermiculite,loam soil

• ruler• thumb tacks• tack board or table

Materials & EquipmentIdea 3 • 30 corn seeds (about

10 seeds for each treatmentand 10 untreated forcomparison)

• small plastic storage bags• absorbent material such as

paper towel, cotton batting,coffee filters, filter paper

• vinegar• baking soda solution• thumbtacks• tack board



Figure 1.22 These plants can use roots to reproduce.

Reproduction without SeedsSeed plants don’t always reproduce from seeds. Reproduction ofplants that doesn’t involve seeds is called vegetative reproduction.Plants produced by vegetative reproduction are geneticallyidentical.

Some plants reproduce from stems. Some produce runners,which are long stems that grow along thesurface of the soil. Other plants produce newstems that run underground called rhizomes.Other underground stems are produced closeto the plant to make the structures we callbulbs, tubers, and corms.

Some seed plants reproduce from theirroots. New plants that form on roots arecalled suckers.

Growers often use these other ways ofreproduction to produce plants. Thehorticultural industry produces many of theplants you see in nurseries using vegetativereproduction. For example, the millions ofspring bulbs sold each year are produced thisway. Suckers are used to produce new plantsof fruit trees and berry plants.

Figure 1.21 These plantscan use stems toreproduce.



Technology to Reproduce PlantsGrowers also produce plants from cuttings and by grafting. Cuttingsare small pieces of a plant that usually have a part of the stem anda few leaves. Almost all plants can produce new roots from a cutstem under the right conditions. Grafting is attaching a part of oneplant onto another plant. Usually, a small branch of one plant isgrafted. The two sections eventually grow together.

Figure 1.24 The cut pieces from another tree will eventually become a part of this one.

CHECK AND REFLECT

1. Draw a diagram of the life cycle of seed plants. Label each stage.

2. What is a pollinator? What attracts pollinators to flowers?

3. Describe two ways that a seed plant can reproduce withoutseeds.

4. Describe how a nursery might produce petunias to sell asbedding plants.

5. What did you learn about conifer trees in this section that youdidn’t know before?

Figure 1.23 New rootscome from the stem,making a whole new plant.

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A Plant PuzzleMany of the plantsthat humans grow areseedless, such asseedless grapes andoranges. How dogrowers reproducethese plants?



B E N E A T H Y O U R F E E T

Seed plants come in many shapes and sizes. Even though plants may look verydifferent, you can usually find roots, a stem, leaves, and reproductive structures.

Look at these photographs of seed plants. Identify all the plant parts you canfind for each one.

When you have identified all the plant parts you can, discuss with anotherstudent the differences in the plants in the pictures. What is different about theleaves? How about the stems?

Can you think of a reason why these structures are so different?


Figure 1.25 Figure 1.26 Figure 1.27 Figure 1.28 Figure 1.29 Figure 1.30

Needles and LeavesPine and fir trees have leaves shaped likeneedles. The leaves of raffia palm can growup to 20 m long and 2.4 m wide!

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1.4 Plant Structures Are Adapted To Their Environment

After a day of cross-country skiing, wouldn’t it be great to comehome and refresh yourself with an orange picked fresh off your owntree? Of course, this could never happen. Orange trees don’t growoutdoors in Alberta because it’s far too cold. But other trees, such ascottonwood and white pine, are able to grow in cold climates.



ProblemSolving

Act iv i ty

CR E AT I N G A LE S S O N AB O U T FL O W E R S

Recognize a NeedYou’re a teacher for a class of grade 1 students. Your students are learning thenames for the parts of plants. Some of them are having a really hard time. Everytime you show them a plant they haven’t seen before, they can’t name any of theparts! You need to come up with a fun way of showing your students lots ofexamples of the parts of plants. You’re going to work with a friend to come upwith a plan for showing them variations in flowers.

The ProblemCreate a fun and interesting way to present variations in flowers.

Criteria for SuccessFor your lesson to be considered successful, it must• show five different kinds of flowers with their parts labelled• be creative and fun to watch• take no more than 10 min to present

Brainstorm Ideas1 Discuss with your partner what kind of flower variations you will present.

Decide which of your ideas is most interesting and unusual.2 Write a list of things you might do to present your flowers. Be creative!

Maybe you can make a video, or write a song. You might want to create agame for the children to play.

Prepare to Present Your Lesson3 Find the examples of flowers you need and transfer them onto the media you

plan to use. For example, you might need to print out pictures from theInternet, or make costumes that look like different flowers.

Test and Evaluate4 Practise your lesson presentation. Depending on what you have decided to

do, you will have to do this in different ways. You might need to rehearse askit or test your game on other students.

5 Make any changes to your presentation that you want after you have finishedtesting. You might want to test it again if you have time.

Communicate6 It’s show time! Present your lesson to the rest of your class. How did it go?

Be considerate and pay attention when other students are presenting theirlesson. Take notes on what you liked most about the other presentations.

7 Write a paragraph on your experience creating a lesson. Compare yourpresentation with the other presentations. What was hardest about solvingthis problem?



PLANTS ARE ADAPTED TO THEIR ENVIRONMENTS

When you walk into a plant nursery or go for a nature walk, you seeall different sizes and shapes of plants. One of the reasons thatplants are different is that they grow in different environments. Tosurvive in a specific environment, plants must be adapted to thatenvironment. That means that they have structures that help themsurvive in that environment. Figure 1.31 describes some of themany ways that plants are adapted to different environments.

Figure 1.31 How are theseplants adapted to theirenvironment?

In dry environments, plantshave to save as much water asthey can. The stems of cacti arethick because they store water.Cactus leaves are tiny spinesthat protect the stem and itsstored water from predators.

Plants like grasses have narrow thin leaves, so they can get many individualsin one place. This helps them to be pollinated by the wind. The depth ofgrass roots helps grasses adapt to occasional drought conditions. Otherplants, like the sunflower, have large, wide leaves to catch lots of sun. Manyplants produce bright flowers and sweet nectar to attract insects like bees,which pollinate the plants as they go from flower to flower.


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Plants such as white spruce treeshave thin needle-like leaves with athick resin coating. This protects theplant from drying out.

Some plants have fibrous roots,which form a thick mat that gatherswater at the upper layers of the soil.Others have long taproots. Theseplants can get water deep down thatothers can’t reach.

Adapted to short growing seasons, some native plants suchas wild mustard produce seeds in less than two months.

Understanding Structures and Life Processes of Plants Helps Us to Interpret Their Needs



Plant Structures and EnvironmentsIn this subsection, you have looked at examples of variations inplant structures, such as leaves, stems, and roots. The wide range ofdifferences in plant structures shows how plants are successfullyadapted to different environments.

CHECK AND REFLECT

1. Sketch a plant with fibrous roots and a plant with a taproot.

2. Describe two examples of variations in leaves that make a plantbetter suited to a specific environment.

3. Why do cacti have thick stems?

4. What kind of environments do you think these plants areadapted to?

Figure 1.32 The bird of paradise flower has a unique structure.

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Plants in ExtremeEnvironmentsEven from a distance,the slopes of theRocky Mountainsabove the treelinelook barren and cold.Find out what types ofplants live on or nearthe tops of theRockies, and how theyare adapted to thisharsh environment.


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